Gripper bar mount for platen press

ABSTRACT

A device for accurately centering the gripper bars carried by a pair of endless chains, in a desired working position in a press. Gripper bars are rigidly secured at their opposite ends to the endless chains during movement of the chains and when chain movement stops, the gripper bars are released from the chains for limited freedom of movement and means then cooperate with the freed gripper bars to positively accurately center the bars.

United States Patent Inventor Pierre Lang Vaud, Switzerland Appl. No.782,191 Filed Dec. 9, 1968 Patented May 4, 1971 Assignee J. Bobst 8:Fils S. A.

' Lausanne, Switzerland Priority Dec. 11, 1967 I Switzerland GRIPPER BARMOUNT FOR PLATEN PRESS 14 Claims, 7 Drawing Figs. US. (l 93/58.3, 93/1,198/19,198/180 lnt. CL B3lb l/20, B31b 17/02,B65g 17/14 Fieldofs'earch93/1 (G), 58.3; 198/19, 180

[56] References Cited UNITED STATES PATENTS Re25,886 10/ 1965 Cargill198/ 1 9X 2,425,039 8/ 1 947 Luehrs 93/1 2,949,066 8/ 1 960 Labombard93/58.=3 2,974,572 3/1961 Shields 93/ 58.3 2,995,233 8/1961 Peras 198/19FOREIGN PATENTS 1,234,088 10/1960 France 93/58.3

Primary ExaminerWayne A. Morse, Jr. Attomey-l-lill, Sherman, Meroni,Gross & Simpson ABSTRACT: A device for accurately centering the gripperbars carried by a pair of endless chains, in a desired working 1position in a press. Gripper bars are rigidly secured at their op-'posite ends to the endless chains during movement of the chains and whenchain movement stops, the gripper bars are released from the chains forlimited freedom of movement and means then cooperate with the freedgripper bars to positively accurately center the bars.

Patented May 4, 1971 3 Sheets-Sheet l ATTORNEYS Patented May 4, 1971 3Sheets-Sheet 2 INVENTOR.

Patented Ma 4,1971 3,577,834

3 Sheets-Sheet 5 INVENTOR.

GRIPPER BAR MOUNT FOR PLATEN PRESS BACKGROUND OF THE INVENTIONLarge-scale presses are now employed in the paper and cardboard industrywhich are designed for the purpose of handling multiple sheet stock. Inaddition to printing type presses such presses may for instance comprisemachines known in the industry as die-cutters and creasers. Theillustrated embodiment of the instant invention relates specifically tosuch die-cutter equipment although the invention will be found to havewidespread utility.

In general, a die-cutting and creasing press may include a stationaryupper platen and a relatively movable lower platen (or vice versa) whichconstitute the mating parts of the press. One or more of the platenscarries tools on its working face (such as slitter blades, creasingrules and the like) so that by bringing the platens into contact withone another under high pressures, 800 tons or more, for instance, with asheet of paper, cardboard or fiberboard, for, instance, sandwichedtherebetween, crease lines and cutouts in such sheet stock can be madeat desired points.

In automatic presses of this type sheets may be fed between the platens,worked, and removed from the platen interface at speeds upwards of ,000sheets per hour.

To provide for the speedy passage of sheets through such presses twosets of endlm chains are provided which are trained over drive and idlerwheels and which chains carry a plurality of gripper bars extendinglaterally across the machine and connected at their outer ends to thechains. The bars carry gripper fingers or other sheet gripping meanswhich "grip" a sheet so that as the chains move, the gripped sheet ispulled through the machine to the working station. The chains then stopso that a sheet is approximately registered in its proper position atthe platen interface and the platens are closed together to perform thedie-cutting and creasing operation. Assuring that the sheet will bepositioned in its exact registry position before the platens closetogether has been difficult in the past and it is the purpose of thisinvention to provide for just such exact registry in a simple andexpeditious manner.

It is therefore an important object of this invention to provide animproved means for accurately registering an intermittently movablechain-carried gripper bar in a sheet fed press.

It is a more specific object of this invention to provide an as semblywherein the gripper bars in a sheet fed press are rigidly afiixed to theconveying chains during movement of the chains and in which the bars arereleased for limited freedom of movement from the chains when the chainsare stopped and wherein means are then provided for registering thegripper bars independently of the chains.

These and other objects, features and advantages of the presentinvention will become apparent from time to time as the followingspecification proceeds and with reference to the following drawingswherein:

FIG. 1 is a diagrammatic view of a platen press showing an endless chaintrained over a pair of wheels and showing the working part of the pressschematically in cross section;

FIG. 2 is a plan view of an end of a gripper bar showing with twoopposed arrows the connection point between the gripper bar assembly andthe endless chain;

FIG. 3 is an enlarged, fragmentary, horizontally sectioned view of thegripper bar assembly at the chain connection point;

FIG. 4 is a vertical sectional view taken along the line IV-IV of FIG. 2and through the gripper bar assembly at the chain connection pointshowing the relative disposition of parts when the gripper bar isrigidly afiixed to the chain during chain travel;

FIG. 5 is a fragmentary vertical sectional view much like that of FIG. 4but showing the relative disposition of parts when the gripper barassembly is released from the chain for limited freedom of movement aswhen the chain has stopped press;

FIG. 6 is a front elevational view of the centering mechanism for thegripper bar assembly; and

FIG. 7 is a side elevational view of that centering mechanism showingsome parts in elevation and others in vertical section.

FIG. 1 illustrates diagrammatically the design of a wellknown form ofplaten press such as is used for die-cutting and creasing operations. Itcomprises generally a main frame I having a heavy fixed upper platen 2secured thereto and a pair of drive sprockets of wheels 3 and 4rotatably mounted thereon.

A conveyor, here illustrated as comprising on endless chain 5 is trainedover the wheels 3 and 4 and is intermittently driven in the direction ofthe arrow by the drive sprocket 3. One such wheel and chain combinationis located on each side of the machine.

A plurality of gripper bar assemblies 6, 7, 8, 9, and 10 are provided tocarry sheets through the press and these gripper bars are connected attheir ends in equally spaced'relation to the chains on opposite sides ofthe press.

A heavy movable lower platen 11 is mounted on the frame and is adaptedto move toward and away from the working lower face of the upper platen2. The mating faces of the two platens carry complementary workingtools, (such as slitter blades, creasing rules or the like), so thatwhen the platens engage one another with a paper sheet sandwichedtherebetween the desired cutting or creasing action will take place onthe sheet.

The gripper bar assemblies each include a plurality of gripper barfingers such as the fingers 12 illustrated in FIG. 2 and these fingersopen and close (somewhat like clothespins) to grip the sheet S.

The chains 5 are successively set in motion and stopped when the platensare separated so that after each press operation a new sheet is carriedby the gripper bar assemblies and chains into position between theplatens. With the chains stopped and a sheet lying between the platens,the platens are brought together to apply pressure to the sheet and thisprocess may be performed at a rate of 5,000 times per hour or more. Eachsheet is held in this so called working position by the gripper barassembly at location 7 and in this position the sheet and hence the barat 7,should be accurately positioned or registered."

It is the purpose of this invention to provide for the exactregistration of the gripper bars at the working station in the directionof their displacement (laterally in relation to the bar andlongitudinally in the direction of the press), and hence for the exactregistration of the sheet carried by the bars in a simple, accurate andexpeditious manner. Gripper bar centering in the longitudinal sense(lateral in relation to the press) is carried out in the usual way andconsists in guide rails in the press for guiding, in the present case,the carrier assemblies from one end of the press to the other.

FIGS. 2 through 5 illustrate the connection between the chains and thegripper bar assemblies. A gripper bar carrier 13 has an enlarged openend 14 within which is fitted the outer end 15 of gripper bar 7. A pairof chain pins 16 and 17 are mounted on the carrier and each of thesepins serves as a means of connecting the carrier 13 into one of theendless chains 5 so that the carrier becomes a fixed part of the chain.The arrows in FIG. 2 illustrate diagrammatically this connection withthe chain. A cover plate 18 is secured to the carrier body by screws18a. The carrier body 13 has a circular opening 19 formed therein.

A pair of openings 20 and 21 are formed within the carrier 13 onopposite sides thereof and these openings receive, without clearance attheirsides, the two opposed, tenons 22 and 23, respectively, of thegripper bar 7. The openings 20 and 21 are enlarged in a verticaldirection somewhat more than the vertical height of the tenons to permitlimited vertical movement of the tenons within the openings. The end 15of the gripper bar 7 which is fitted within the carrier is narrower thanthe distance between the opposed inner sidewalls 14 of the carrier sothat a clearance 24 is provided between the inner carrier walls and thegripper bar.

As a result, all axial movement of the bar 7 is opposed but av smalldegree of lateral movement in the direction of sheet conveyance ispermitted.

In order to ensure that the gripper bar will be locked in a fixedposition relative to the chain during movement of the chain, a lockingpiston 25 is provided. The piston 25 has an enlarged base 26, atruncated shoulder 27, and a cylindrical upper portion 28 terminating inan end face 29. The piston base 26 is slidably guided for rectilinearmovement within a well 30 formed in the base wall of the cover 18. Anopening 31 is formed within the end of the gripper bar 7 and thisopening is defined by a chamfered edge 32 which is complementary withthe truncated portion 27 of the piston 25. The cylindrical portion 28 ofthe piston is snugly fitted within the opening 19 so that upwardmovement of the piston (guided within well 30 and opening 19) will actthrough cooperation of the truncated section 27 of the piston and thecomplementary bevel 32 to center the bar end 15 in the carrier 13 andpositively fix the two in relation to one another. In fact, a springwhich may comprise a plurality of Belleville washers 33, is providedwithin the hollow interior of the piston and between the end face 29 andthe base of the cover l8 to urge the piston to the extended positionshown in FIG. 4. A centering post 34 is provided to center the washersand tenninates at a point sufficient to permit the piston to move to theposition illustrated in FIG. 5.

In order to free the bar relative to the carrier 13 it is only necessaryto press downwardly on the end face 23 of the piston against theopposing bias of the Belleville washers to seat the piston within thewell and separate the complementary surfaces 27 and 32. At such time thepiston occupies the position illustrated in FIG. 5 and the gripper baris free to move laterally within the carrier to the extent of theclearance 24 while axial gripper bar movement is prevented by reason ofthe close fit of the tenons in the sides of the openings 20 and 21. Thisfreed" position of the gripper bar in the carrier occurs at the timethat exact registration of the bar takes place.

Gripper bar centering is achieved by means of assemblies best viewed inFIGS. 6 and 7.

A block 35 is secured to one side of the movable lower platen 11 andthis block carries a pair of running rollers 36, 37 mounted on pins 36a,37a. The block 35 thus rises and falls with the lower platen 11 andoccupies the upper position illustrated in FIG. 7 only when the chainhas come to a rest and pressure is to be applied to the sheet by theplatens. In FIG. 7 may be seen the working tools comprising a chase 38carrying a plurality of knives or rules 39 and a counter plate 40against which the blades or rules work. Rollers 38a facilitatewithdrawal of the chase 38 from the press. The rollers 36, 37 protrudeslightly above the upper plane of the block 35 and are so positioned asto engage the under surface of the end of the gripper bar 7, when thebar has been freed from the carrier assembly as will hereafter beexplained. The upper surface of the block 35 is adapted to engage theunder surface of the cover plate 18 as the lower platen (and hence theblock 35) moves upwardly.

A stem 41, carried by a supporting frame 42, has its lowermost endposition in the path of movement of the piston 25. A spring which maycomprise a series of Belleville washers 43, acts downwardly on the stem41 and has a greater spring bias than the washers 33 so that when thecarrier assembly begins to move upwardly, the lower end face of the stem41 engages the piston 25 to provide the downward force on the pistonnecessary to free" the gripper bar from the carrier 13 (such freedposition being shown in FIG. 5). 7

FIG. 6 illustrates the disposition of various parts of the assembly justat the moment of contact of stem 41 with the upper end face 29 of piston25. At such time it will be noted that the block 35 supports the undersurface of the cover plate 18 and that the clearance at point 36bbetween the rollers 36, 37 and the bar 7 is about one-half that of theclearance 7a between the bar 7 and the cover plate 18. As a consequence,depression of the plunger 25 permits the bar 7 to fall within thecarrier assembly until the bar comes to rest on the rollers 36, 37.

The gripper bar 7 is thus freed from the carrier for limited lateraldisplacement and the ends of the gripper bar rest on the rollers such as36, 37 so that the final centering or registration step can take place.Final registration is accomplished by means of a second stem 44supported for limited vertical movement in the frame 42 and biaseddownwardly by a spring 45 or a series of Belleville washers.

The lowermost end of the stem 44 is provided with an elongated V-shapedgroove which is complementary with a fitting 46 having a roofiikeconfiguration and secured to the gripper bar 7 as shown in the otherFIGS. The fitting 46 is screwed to the bar by means of the screw 46a andmeans (not shown) are provided for the purpose of ensuring that theplanes of the complementary beveled surfaces of the stem 44 and fitting46 are always normal to the major axis of the machine.

As the bar 7 moves upwardly, it is first freed for limited movement fromthe carrier 13 and is the centered accurately forwardly or rearwardly ofthe rest position of the carrier through the means of the V-notched stemand the complementarily ridged fitting 46. Stem 41 causes bar releaseand stem 44, bar centering.

Exact registration of the gripper bar at the working station is therebyattained while at the same time means have been provided to assure thatthe gripper bar will be fixedly carried by the chain during thatinterval when the chain is moving.

Lastly, it should be understood that while the invention will probablypresently find its principle utility in connection with chain drivenunits, other conveyor means than chains might well be employed withequal facility such for example as endless belts, cables, or the like.

I claim:

1. In a press wherein sheets are carried to a working station by aconveyor driven gripper bar the improvement which comprises:

a carrier fixedly coupled to the conveyor,

a gripper bar, coupling means connecting said gripper bar to saidcarrier, said coupling means allowing free motion between said gripperbar and said carrier so that said gripper bar is never independent ofthe chain and stops when the chain stops, centering means registeringsaid gripper bar within said carrier when said gripper bar is releasedfrom said carrier.

2. In a press including intermittently moving chains and a gripper barfor carrying stock to a working station within said press, theimprovement comprising:

a carrier assembly integrally connected into a portion of said chain,

a gripper bar movably mounted on said carrier assembly,

centering means urging said gripper bar to a predetermined centeredposition within said press in one position of said chain, and

means fixedly mounting said gripper bar within said carrier assembly inanother position of said chain.

3. The device recited in claim 2 wherein said gripper bar is permittedfreedom of movement with respect to said carrier assembly only in adirection transverse to the longitudinal axis of said gripper bar.

4. The device recited in claim 2 wherein said centering means urges saidgripper bar to a predetermined centered position within said press whensaid chains have stopped and wherein means fixedly mount said gripperbar in said carrier when said chains are moving and release said gripperbar for limited freedom of movement in said carrier assembly when saidchains are stopped.

5. The device recited in claim 2 wherein said centering means urges saidgripper bar to a predetermined centered position within said press whensaid chains have stopped and wherein means fixedly mount said gripperbar in said carrier when said chains are moving and release said gripperbar for limited freedom of movement in said carrier assembly when saidchains are stopped and wherein said gripper bar is permitted freedom ofmovement with respect to said carrier assembly only in a directiontransverse to the longitudinal axis of said gripper bar.

6. in a platen press including a pair of mating platens, a pair ofendless intermittently moving chains on opposite sides of the press andat least one gripper bar connected at its ends to said chains forcarrying stock to a working station within the press, and wherein thechains are brought to rest each time a gripper bar advances t a workingstation, the improvement which comprises:

a carrier assembly fixedly connected to each said chain, and

receiving an end of said gripper bar,

interengagement means on the ends of each said gripper bar and saidcarrier assembly cooperating to prevent movement of said gripper baralong its axis relative to said carrier assemblies,

said gripper bar having limited freedom of lateral movement within saidcarrier assemblies,

a vertically movable at least partially conically configurated pistonmounted on said carrier and extending through an opening in said gripperbar,

whereby movement of said piston in one direction will engage the conicalportion of said piston with the portion of said gripper bar definingsaid opening, to lock; said gripper bar and said carrier assemblytogether 'and whereby movement of said piston in an opposite directionwill disengage said piston and gripper bar to free said bar,

a centering fitting extending outwardly from said gripper bar,

means raising and lowering said gripper bar simultaneously with closingand opening movement respectively of said platens,

abutment means disposed in the path of said piston during closingmovement of said platens to engage and move said piston to free saidgripper bar for limited freedom of movement within said carrierassembly, and

a centering abutment having an inverted tapered surface engageable withsaid centering fitting during closing movement of said platens as saidgripper bar is freed for limited movement from said carrier assembly.

7. The structure of claim 6 wherein said centering fitting has aroof-shaped profile with the roof ridge parallel to the axis of saidgripper bar and said centering abutment has an inverted roof-shapedprofile likewise oriented.

8. The structure of claim 6 wherein spring means bias said piston in onedirection and wherein piston engagement with said abutment means movesthe piston in an opposite direction and wherein said abutment means andsaid centering abutment are resiliently supported on said press.

9. In a platen press including sets of gripper bars for conveying sheetsto a working station wherein the bars are connected at their ends to apair of intermittently movable chains, the improvement which comprises:

carrier means connecting the bar ends to the chain and providing play inthe conveying direction,

means interconnecting the carrier means and the bar rigidly during chainconveyance,

means releasing said bar from said carrier means to accommodate saidplay when said chains have stopped,

and means including a cooperating centering element on the frame of saidpress and on said gripper bar for centering said gripper bar when saidbar release takes place.

10. A press according to claim 9, in which each bar end is engaged withlateral play but without axial play into a carrier assembly box integralwith the corresponding chain.

11. A press according to claim 10, in which a member extends through thebar and atleast a wall of the box perpendicularly to the working plan,which member protrudes from the box under the action of springs andlocks the bar in fixed position through the cooperation of a frustum onthe member and a cooperating seat of same profile on the bar, wherebypushing back the said member against the opposing action of the springswill restore the free play of the bar.

12. A platen press according to claim 6 wherein the means raising andlowering said gripper bar comprise a block engageable with said carrierassembly and rollers mounted with said block on a moving platen, whichsaid rollers are engageable with the said gripper bar in the freedposition of said bar so as to facilitate displacement of the bar in thesense of its lateral play.

13. A platen press according to claim 9 wherein the means raising andlowering said gripper bar comprise a block engageable with said carrierassembly and rollers mounted with said block on a moving platen, whichsaid rollers are engageable with the said gripper bar in the freedposition of said bar so as to facilitate displacement of the bar in thesense of its lateral play.

14. The platen press of claim 6 wherein said interengagement meanscomprise tenons extending horizontally outwardly from a perpendicular tothe longitudinal axis of said gripper bar and vertically enlarged slotsformed in said carrier assembly and snugly receiving the tenons alongthe side edges of the slots.

1. In a press wherein sheets are carried to a working station by aconveyor driven gripper bar the improvement which comprises: a carrierfixedly coupled to the conveyor, a gripper bar, coupling meansconnecting said gripper bar to said carrier, said coupling meansallowing free motion between said gripper bar and said carrier so thatsaid gripper bar is never independent of the chain and stops when thechain stops, centering means registering said gripper bar within saidcarrier when said gripper bar is released from said carrier.
 2. In apress including intermittently moving chains and a gripper bar forcarrying stock to a working station within said press, the improvementcomprising: a carrier assembly integrally connected into a portion ofsaid chain, a gripper bar movably mounted on said carrier assembly,centering means urging said gripper bar to a predetermined centeredposition within said press in one position of said chain, and meansfixedly mounting said gripper bar within said carrier assembly inanother position of said chain.
 3. The device recited in claim 2 whereinsaid gripper bar is permitted freedom of movement with respect to saidcarrier assembly only in a direction transverse to the longitudinal axisof said gripper bar.
 4. The device recited in claim 2 wherein saidcentering means urges said gripper bar to a predetermined centeredposition within said press when said chains have stopped and whereinmeans fixedly mount said gripper bar in said carrier when said chainsare moving and release said gripper bar for limited freedom of movementin said carrier assembly when said chains are stopped.
 5. The devicerecited in claim 2 wherein said centering means urges said gripper barto a predetermined centered position within said press when said chainshave stopped and wherein means fixedly mount said gripper bar in saidcarrier when said chains are moving and release said gripper bar forlimited freedom of movement in said carrier assembly when said chainsare stopped and wherein said gripper bar is permitted freedom ofmovement with respect to said carrier assembly only in a directiontransverse to the longitudinal axis of said gripper bar.
 6. In a platenpress including a pair of mating platens, a pair of endlessintermittently moving chains on opposite sides of the press and at leastone gripper bar connected at its ends to said chains for carrying stockto a working station within the press, and wherein the chains arebrought to rest each time a gripper bar advances to a working station,the improvement which comprises: a carrier assembly fixedly connected toeach said chain, and receiving an end of said gripper bar,interengagement means on the ends of each said gripper bar and saidcarrier assembly cooperating to prevent movement of said gripper baralong its axis relative to said carrier assemblies, said gripper barhaving limited freedom of lateral movement within said carrierassemblies, a vertically movable at least partially conicallyconfigurated piston mounted on said carrier and extending through anopening in said gripper bar, whereby movement of said piston in onedirection will engage the conical portion of said piston with theportion of said gripper bar defining said opening, to lock said gripperbar and said carrier assembly together and whereby movement of saidpiston in an opposite direction will disengage said piston and gripperbar to free said bar, a centering fitting extending outwardly from saidgripper bar, means raising and lowering said gripper bar simultaneouslywith closing and opening movement respectively of said platens, abutmentmeans disposed in the path of said piston during closing movement ofsaid platens to engage and move said piston to free said gripper bar forlimited freedom of movement within said carrier assembly, and acentering abutment having an inverted tapered surface engageable withsaid centering fitting during closing movement of said platens as saidgripper bar is freed for limited movement from said carrier assembly. 7.The structure of claim 6 wherein said centering fitting has aroof-shaped profile with the roof ridge parallel to the axis of saidgripper bar and said centering abutment has an inverted roof-shapedprofile likewise oriented.
 8. The structure of claim 6 wherein springmeans bias said piston in one direction and wherein piston engagementwith said abutment means moves the pIston in an opposite direction andwherein said abutment means and said centering abutment are resilientlysupported on said press.
 9. In a platen press including sets of gripperbars for conveying sheets to a working station wherein the bars areconnected at their ends to a pair of intermittently movable chains, theimprovement which comprises: carrier means connecting the bar ends tothe chain and providing play in the conveying direction, meansinterconnecting the carrier means and the bar rigidly during chainconveyance, means releasing said bar from said carrier means toaccommodate said play when said chains have stopped, and means includinga cooperating centering element on the frame of said press and on saidgripper bar for centering said gripper bar when said bar release takesplace.
 10. A press according to claim 9, in which each bar end isengaged with lateral play but without axial play into a carrier assemblybox integral with the corresponding chain.
 11. A press according toclaim 10, in which a member extends through the bar and at least a wallof the box perpendicularly to the working plan, which member protrudesfrom the box under the action of springs and locks the bar in fixedposition through the cooperation of a frustum on the member and acooperating seat of same profile on the bar, whereby pushing back thesaid member against the opposing action of the springs will restore thefree play of the bar.
 12. A platen press according to claim 6 whereinthe means raising and lowering said gripper bar comprise a blockengageable with said carrier assembly and rollers mounted with saidblock on a moving platen, which said rollers are engageable with thesaid gripper bar in the freed position of said bar so as to facilitatedisplacement of the bar in the sense of its lateral play.
 13. A platenpress according to claim 9 wherein the means raising and lowering saidgripper bar comprise a block engageable with said carrier assembly androllers mounted with said block on a moving platen, which said rollersare engageable with the said gripper bar in the freed position of saidbar so as to facilitate displacement of the bar in the sense of itslateral play.
 14. The platen press of claim 6 wherein saidinterengagement means comprise tenons extending horizontally outwardlyfrom a perpendicular to the longitudinal axis of said gripper bar andvertically enlarged slots formed in said carrier assembly and snuglyreceiving the tenons along the side edges of the slots.